Regular physical activity has important and wide-ranging health benefits. People with at least a moderate level of fitness have less chronic disease, and, importantly, when moderately fit people do have a chronic disease they live longer lives. Church and Blair
followed 2,316 men with type-2 diabetes for 15.9 years. They sorted the results by into three groups of BMI (18.5 to 25; 25.1 to 30; and 30.1 to 35) and by fitness level (low, middle, and high).
The expected result is that in every BMI group, the mortality of people with low fitness was two times higher than people with even moderate fitness.
The unexpected result is that obese men (BMI 30 to 35) who were moderately or highly fit had less than half of the risk of dying as normal weight men (BMI 18.5 to 25) who were unfit.
Wow, that's an impressive result. The recommendation could not be clearer: being active lowers mortality rates, even for obese diabetics.